Join Jo: Using Natural Colorants in Soap with Your Lye Solution

One of my favorite ways to use botanicals in soap is to make soap with the plant colorant directly in the lye solution!

Madder (Rubia tinctorum), indigo (Indigofera Tinctoria), and manjistha (Rubia Cordifolia) are three natural colorants that can be used straight into the lye solution to bring out their best color.

Madder and manjistha will give a gorgeous pink, depending on the amount you use. The color can range from a dusky pale pink right though to a dark pink, but be careful using too much, it can give pink bubbles and be hard to remove from white cloths and baths!

Indigo will give a color range from a beautiful robin’s egg blue right through to navy blue and almost black. Again, be aware that you may have colored lather and the color may be hard to remove from white cloths and baths.

For your first time using any natural colorant in your lye solution, don’t worry about straining it, just try using the colorant and see what the results are. Next time you use the natural colorant, you will know the color to expect and can adjust the amount used. If you don’t want specks in your finished soap, you will know if you need to strain the lye solution.

Use a soap recipe you are comfortable with, so the only new technique will be using the colorant in your lye solution. Remember to use the whitest oils you can so that you can see the gorgeous color at the end, and remember to gel to get the full impact!

I use 2.5 tablespoons of madder root for a 5 lb soap batch (roughly ½ tablespoon per pound of oils) – for a dusky pastel pink. I use the same amount of manjistha for a brighter pink and I use ½ teaspoon of indigo powder for a denim blue. If you would like a brighter pink you can use 1 tablespoon per pound of oils for the madder and manjistha.

Using Natural Colorants in Soap with Your Lye Solution

These photos are of manjistha being used, however, I follow the same procedure for madder root and indigo or any of the other colorants that I use in lye solution.

Measure the amount of colorant you need into a cup. Make your lye solution in the way you normally do, following all the usual safety precautions.

Immediately after you have added the lye to your water and it has dissolved, add your natural colorant. Pour the dry natural colorant straight in your lye solution, and stir it around. You should see something similar to this:

Manjistha added to lye solution

It will look like there are bits in the lye water, and it will look really dark, almost a maroon color. Don’t worry, it won’t stay this color, but this is completely normal!

If you are like me, you like to know what is going on. I keep a dish with cold water next to my lye water and I place the spoon that has been stirring the lye into the dish – to check the color! It’s a great way to see the magic of plant colorants at their best.

The lye solution mixing spoon in a little water

Look at all those specks and look at the gorgeous pink!

This pink color around the edges is very close to the color that the soap will be when wet in the mold. I like to strain my lye solution, so I don’t have those specks. However, you don’t have to do this step.

I am including how I strain for those soapmakers that would like to see how someone else does it. I consider straining the lye solution to be an advanced technique, and encourage you to give this a try without straining first. (Be careful, your lye solution is caustic and can splash! Suit up!)

Filtering the manjistha & lye solution through cheesecloth

As you can see, my filter system is really simple: cheesecloth folded 4 times and placed into a sieve (dedicated to soaping). The sieve is resting on the top of my bucket that already has my base oils in it ready to go.

You will need to use your spoon to encourage all the liquid to pass through the cheesecloth – it does take some time to filter through. Your cloth will have a gorgeous pink to it forever. As you can see, I also use it for woad and indigo as you can spy the blue spots on left of picture. When I have finished with the cloth, I rinse it, wash it, and hang it up to dry ready to go for the next time. Its quite pretty to look at, too!

Once the lye filters through to the oils, it will settle at the bottom of the bucket and you will see this really cool effect!

After adding the lye solution to your base oils, it’ll sink to the bottom!

That is the lye and madder waiting to be stick blended! I love to see the oil on top and the colorant at the bottom.

Now you can make your soap just how you normally do. Stick blend until you get to the amount of trace you like to use. Here is how the manjistha looks once you get to emulsification stage. I love that bright color!

After blending the manjistha lye solution and oils, it turns a beautiful pink!

Pour the soap batter straight into your mold and decorate as you would like. In the following photo, you can see white lines of zinc oxide to give you a reference of the color when wet and fresh in the soap batter.

The raw manjistha colored soap in the mold

You can expect changes to occur whilst the soap is gelling. When you unmold the soap, the color will be quite a bit paler than it was in the mold.

Pink manjistha soap in the mold with a decorated top for contrast

The following photo shows a comparison of French Pink Clay on the bottom, Manjistha root in the middle and Madder root on the top. All three were used directly into the lye water.

From Top to Bottom: French Pink Clay, Manjistha, and Madder Root

Other botanicals to try in your lye solution:

Black walnut hull – brown with pink tone and less speckled than at trace

Calendula petals – bright yellow, pastel if not gelled

Charcoal powder – add less than normal (less specks than if added at trace)

Pumpkin – orange (decrease water amount by the amount of pumpkin puree added)

Carrot – orange (decrease water amount by the amount of carrot juice/pulp added)

A range of naturally colored soaps made by Jo Haslauer

I really hope you have enjoyed the series on using natural colorants in soap making. I love using natural colorants, and really enjoy seeing the changes that occur – I look forward to seeing your beautiful creations using some of these methods!

Jo Haslauer’s soap passions are plant colorants, botanicals & essential oils. She lives in Melbourne Australia, spends her time making soap, infusing herbs, running her business, and trying to demystify the world of plant colorants in cold process soap.

Hi Jo ! First of all, thanks for these great articles about coloring home-made soaps. I just loved them all. I can’t wait to start using plants in my soaps. I had been wanting to do this for a while but had not had the idea of looking information on the internet! How silly ! 😉

However I have a question: how do you proceed with the zinc oxyde to draw those beautiful white marks at the surface of the soap? They are gorgeous and I would love to know how to do this.

Hi Aurelie!
Thank you so much for your kind comment. I am so pleased you are inspired to use plants in your soap making 🙂

Those tops are really thick trace soap that is drawn in a line and swirled around the top of the soap. I find the zinc oxide gives me a good contrast to the base and more than likely that helps make them stand out visually.

Please let us know how you go with the plant colorants when you use them

Thank you for all ! I’m in love with your soaps 😉
Sorry for my english, I’m French and I don’t practice for a long time ^^
I tried orcanette (alkanett in english ? google traduction doesn’t know this word ! but I supposed it is the same I used in my tests).http://lespetitesdouceursdelisabeth.blogspot.fr/2015/05/mes-savons-lorcanette.html
I tried indigo added at trace. My next soap will be in lye solution, I want to have the blue you have got !
The same with madder root : juste a try at trace. I’ve a red soap, not a beautiful rose one.

Hi Tammy,
Yes I use zinc oxide to whiten an area of my soap and I use it exactly the same way as I would use titanium dioxide. I probably use 1 tspn more when I use zinc as its not quite that blinding white that td is. You should try it and see how it works for you. 🙂

I read and haven’t got enough of your informations do you have a page ?
I’ll tried a soap with curcuma powder but now I don’t know.
How do I know what powder use in Lye and what powder I can use as a infusion ?

Hi Phanie!
I infuse my curcuma powder in olive oil and then use that in my soap batter. I add it to the oils before I add the lye and I add it at about 10% of the total amount of oils that I am going to use

For example if I was making a 1000g batch of oils in my soap I would use 900g of my recipe oils and 100g of my curcuma infusion = 1000g

Please dont hesitate to contact me again if you need more help 🙂 it is a different way to make soap I know and can be confusing at first

Hi Susan, yes you definitely can use brewed coffee in lieu of plain water in your lye solution. I found it was not a great smell when I did it and I also found that the dark brewed coffee was not as brown as I had expected it was more a milky coffee colour and I had wanted the dark brown.

In the end I added Hersheys cocoa powder to the batter at trace to achieve the dark colour I wanted.
Hope this helps 🙂

Hi Jo
Than you for answering my last question. I made an indigo coloured soap using your recommended ratios and it came out a lovely dark blue but still had white lather – yay!
Now I’m going to try madder root.
However, my question is how many mls are in your tbsp? I’m in Australia too so 1 aussie tbsp = 20ml. However, I used the US tbsp = 15ml when calculating the indigo as this is a US website and I didn’t notice that you were an Aussie 🙂
It shouldn’t make too much of a difference in large batches but for this test run I’m going to try a teeny batch as I’m also experimenting with tallow and I’ve been caught out with big batches going wrong before (I have over 20 indigo soaps to use up that create a very blue lather)!
Thank you 🙂

How would you add the calendula to the lye solution to get a yellow color? I have a bag of calendula that has whole flower and petals in it. Would I soak it in the lye then drain or should I put the calendula in a coffee grinder and grind it into a powder?
Thanks, love your oh so helpful site 🙂

HI Hollie,
I infuse my calendula in olive oil by the cold infusion method. I just fill the bottle with the petals as much as I can and then fill up the rest of the room with olive oil. I use a 16oz mason jar. The other method I do is I use calendula powder that I buy and use 1oz powder to 15oz oil in the mason jar again.

When I tried adding them to the lye I added them in whilst the lye was hot and then strained the lye before adding it to soap oils. The lye was pretty harsh for them and I got a a pale creamy yellow doing it this way.

If you are wanting a bright sunshine yellow try infusing annatto seeds in oil and then add that oil to your base oil recipe at about 15%. It should be a beautiful buttercup colour 🙂 depending on the other oils you are using of course.

I know this is an older post so I don’t know if you still answer questions on it, but I was wondering if you have ever tried infusing and using beet powder to see how it does? I am new to soaping – have only two batches under my belt, lol – and am wanting to make a loaf of soap that looks like watermelon (like I’m sure you’ve seen). I cannot find a good source (aka, reasonably priced and good shipping price) for madder powder to get a nice red-pink color. I have been infusing some paprika and thought if I mixed it with some of the red Moroccan clay I have (although that clay tends to be more red-brown)….

Thank you for sharing your knowledge and experimenting though. My desire is to make any and all soaps with all natural colorants and either fragrance free or use essential oils. I am very sensitive to chemical fragrances which is what started me on the journey to natural living several years ago. It just took me a while to try making soap because I had a childhood fear (actually, a funny story) of lye. 😉

And then after I post this I realize that manjistha powder is a beet powder….duh! Sorry. I was also wondering about hibiscus powder? Have you tried it. The powder itself looks very pink-red. I may have to buy some to play and see. I love to play when it comes to creating. 😉

Hi Leslie!
Yes I still answer questions that come in – I love talking colorants with people.

Manjistha is similar to madder. I am not sure where you are for suppliers but madder can be found in Indian Shops if you dont want to purchase online?

Beet powder will go brown as will Hibiscus powder. I love both those colours but as a tea and as a power colorant they have both gone brown. Such a shame as they are so beautiful and tempting!!

Red is the elusive natural colorant for us – its proving to be hard to get for all of us – true red. Madder would look good for the watermelon. I would follow the same guidelines as I have shown for the Manjistha – they are interchangeable in how I use them.

Welcome to the addiction that is soap making – the world is your oyster and I look forward to seeing some of your creations in the future!
jo

Hi Jo, I have a couple of questions regarding your zinc oxide swirls. When you said you used thick trace soap colored with the zinc oxide, does that include the soap that you’ve already colored by adding the colorant to the lye in the beginning? Will the zinc oxide work that well? Also, in your book you mention adding the zinc oxide to water but you didn’t say how much water.
Thank you so much for sharing your years of research. I have been wanting to use natural colorants, but I love pretty soaps with lots of swirls, and I couldn’t figure out how to accomplish it. Thanks again!
Paula

Yes you can add the zinc oxide to the soap that is already coloured so that becomes your pale swirl colour. If you add a darker colorant i.e. charcoal to another portion of the batter it becomes the dark swirl. That way you have three different colours from the one already coloured batter. I have had no trouble with the zinc oxide working this way.

The amount of water is enough to make it a slurry so that you can swirl with it. If you are not very confident make the slurry more like a cream however if you want a water flow type slurry then you would use more. Remember to make the slurry the night before so the colorant has time to absorb the water completely.

Thank you so much for your support of my ebook, if you have any more questions please don’t hesitate to ask. Natural colorants are such fun and when you finally get them to work so easy, the challenge in the journey I agree!

Though a newbie, I love purely natural soap. No scents. Natural colorants. But I would love to know, if I add the natural colorant to the lye water without straining, can I still soap with the colored lye water using the heat transfer method? I feel very comfortable with it. Thanks

Yes you definitely can use that for the heat transfer method. The only reason I strain is because I don’t like the specks and some people find madder particularly to have an exfoliating effect. You can follow the colorant in lye water and use that water how you normally do for soaping, there is no reason to wait until cool if that is not your preferred method

JO,
omg- what a disaster. . .another soapy frustration. . .please help. I just made a 3# batch of soap. I followed Kenna’s directions to the letter; mixed my lye and water and then added indigo powder. I added much more than the directions say, more like 1 1/2 tsp. because i wanted a very dark color. I then let the lye come to about 100 degrees and the oils to 85 degrees. I strained through a strainer lined with cheesecloth, then blended and got hardly any blue color. I had to add more indigo to the soap batter- just what i didn’t wnat to do because of the speckles. also at the end of the strain, there was a clumpy mixture left which looked like indigo that didn’t mix. again i added the indigo when the lye was hot.

Did you rehydrate the indigo powder before you added it to the hot lye water? I used pre reduced crystals usually but when i use powder I rehydrate it first, make sure its completely mixed in and add that to the batter at trace.

However recently I had a similar result to you as I made a salt bar and I am sure I strained salt and indigo both out of the mix and had a very very pale looking colour that I was left with. Strangely over the next 7 days as saponification occurred the soap became more blue. I am wondering if that might happen with you?

Did you gel your soap by the way as that will give you the best chance of blue and brings out the colour better for me than if I dont.

I do have some indigo even with the crystals that do not dissolve completely and are left in the cheesecloth at the end, I would think this has happened to you here.

Next time you use powdered indigo, rehydrate it 24 hours before with hot water and mix it really well. You can add this at trace and it doesnt seem that you have a lot of speckles as you have mixed it earlier and the indigo has dissolved into the hot water.

see how you go doing it that way, and if you need to ask more question please dont hesitate – we can do this!

LOVE LOVE your series on natural coloring! I read every one of your article as well as every Q&A under each article, this is super helpful to me.

Quick question regarding straining the dyed lye solution, since you use a cheese cloth, I am sure no matter how hard to press the cheese cloth, there will be some lye solution left behind. Do you worry about not having enough lye for your oil to achieve soaponification?

I use the back of a spoon and I do press quite hard to get all the lye water out. I did measure it once and the missing amount of lye was minute in reality so I dont worry about the tiny bit that is left on the cheesecloth. I have never had an issue with the soap not saponifying and so yes I know there will be a bit left but its not enough to throw out the recipe 🙂

Thanks for all your time and effort making this info available to the public. What a fantastic resource you’ve been!

I have a question about adding the colors with the lye/water. I’m not sure I really want to strain a lye mix, but like you, I’m not a fan of the specks. I’m wondering if you’ve ever tried steeping the madder or indigo in hot water, and then straining and chilling the water before adding the lye? If you’ve tried it, I’d be interested to know how it worked & how it compared to the color you get when you add it to the lye/water.

Stacie there is absolutely no reason you can’t do what you are thinking of doing. Straining lye is not for everyone so yes this would be a perfect way to achieve no specks and not have to strain lye water – perfect !
jo

Hi Jo, I am in the US and was wondering if you could suggest a good place to purchase some of the more obscure herbs? Particularly Ratanjot, Manjistha and Gromwell? Thanks so much, I’ve been soaping for years and have never seen such beautiful natural colors! I can’t wait to try some of your techniques!

Hi Jo. I only just found your site as I was looking for info on natural soap colouring. This is one of the best sites I have come across so far. I live in the UK and the soaping information and resources here are rather limited. I have gotten most of my previous info from US sites. I recently made an all coconut oil soap using soap wild plantain and curly dock leaves as the colourant and it turned out a beautiful leaf green colour. I also used a small amount of blue poppy seeds to give a speckled effect. I was really proud of myself regarding the outcome. I used some chamomile, lavender and bergamot essential oils as fragrance but the outcome was not as nice as I expected. I used these oils mainly because of my husband who has psoriasis and these are some of the recommended oils for it. I blended the freshly picked leaves in premeasured purified water then stained it and kept it in the fridge overnight. I have a passion for herbs both as medicine and in skin care and your articles have given me a lot more insight , especially the one with what EOs to use to enhance the botanical colours.
Thanks a million and God bless.

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[…] (If this describes your soapmaking style, you may also be interested in reading this informative series of posts over at Modern Soapmaking – (1) Coloring Soap Naturally, (2) How to Make Infusion for Soapmaking, (3) How to Use Plant Infusions in Soap Making & (4) Using Natural Colorants in Your Lye Solution.) […]

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